Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
Remove gas valve, fan and burner assembly

Observation:

Thoroughly check spark electrode for cracks and damage to the electrode ceramics and good general condition.
Check for correct spark gap.
Gap should be 4 mm and the electrode should be 6mm from the burner +/- 0.5 mm.
Note:
Inspect all gaskets and replace as per the manufacturer’s instructions.
Refer to adapt for guidance on gasket replacement.